<template>
  <div class="list" ref='wrapper'>
    <div>  
      <div class="area">
          <div class="title border-topbottom">当前城市</div>
          <div class="button-list">
              <div class="button-wrapper">
                  <div class="button">{{this.currentcity}}</div>
              </div>
          </div>
      </div>
      <div class="area">
          <div class="title border-topbottom">热门城市</div>
          <div class="button-list">
              <div 
                class="button-wrapper" 
                v-for="item of hot" 
                :key="item.id"
                @click='handleCityClick(item.name)'
              >
                  <div class="button">{{item.name}}</div>
              </div>
          </div>
      </div>
      <div 
        class="area" 
        v-for="(item,key) of cities" 
        :key="item.id"
        :ref='key'
      >
          <div class="title border-topbottom">{{key}}</div>
          <div class="item-list">
              <div 
                  class="item border-bottom"
                  v-for="innerItem of item"
                  :key="innerItem.id"
                   @click='handleCityClick(innerItem.name)'
              >
                  {{innerItem.name}}
              </div>
          </div>
      </div>
    </div>
  </div>    
</template>

<script>
import BScroll from 'better-scroll'
import {mapState,mapMutations} from 'vuex'
export default {
    name:'CityList',
    props:{
        hot:Array,
        cities:Object,
        letter:String,//接收兄弟组件组件传来的数据
    },
    computed:{
        ...mapState({
            currentcity:'city'
        })
    },
    methods:{
        handleCityClick(city){
            // console.log(city)//city为什么能获得点击的数据???
            // this.$store.commit('changeCity',city);
            this.changeCity(city);
            this.$router.push('/');//xunan选择后立即实现页面跳转
        },
        ...mapMutations(['changeCity'])
    },
    watch:{
        letter(){//侦听器侦听lette,一旦letter数据发生变化就作出反应
          if(this.letter){
              const element=this.$refs[this.letter][0];//this.letter，这里不加[0]的话输出的会是一个数组
              this.scroll.scrollToElement(element);//scrollToElement(一个元素/选择器),iScroll将尝试滚动到这个元素的左上角位置
          }
        }
    },
    mounted(){
        this.scroll=new BScroll(this.$refs.wrapper)
    }
}
</script>

<style scoped>
.border-topbottom:before,.border-topbottom:after{
border-color:#ccc;
}
.border-bottom:before{
border-color:#ccc;
}
.list{
    position: absolute;
    top:1.58rem;
    left:0;
    right:0;
    bottom:0;
    overflow: hidden;
}
.title{
    line-height: 0.54rem;
    background: #eee;
    padding-left:0.2rem;
    color:#666;
    font-size:0.26rem;
}
.button-list{
    overflow: hidden;
    padding:0.1rem 0.6rem 0.1rem 0.1rem;
}
.button-wrapper{
    width:33.33%;
    float: left;
}
.button{
    margin: 0.1rem;
    padding:0.1rem 0;
    text-align: center;
    border:0.02rem solid #ccc;
    border-radius: 0.1rem;
}
.item{
    padding-left:0.2rem;
    line-height: 0.7rem;
}
</style>